docs: def get_closest(self, sma):
          """
          Return the `~photutils.isophote.Isophote` instance that has the
          closest semimajor axis length to the input semimajor axis.
  
          Parameters
          ----------
          sma : float
              The semimajor axis length.
  
          Returns
          -------
          isophote : `~photutils.isophote.Isophote` instance
              The isophote with the closest semimajor axis value.
          """
  
          index = (np.abs(self.sma - sma)).argmin()
          return self._list[index]